Method for manufacturing a transparent gas barrier film

ABSTRACT

A method for manufacturing a transparent gas barrier film for an organic electroluminescence element having a substrate with a gas barrier layer thereon. The gas barrier layer is formed on the substrate by plasma CVD using an organic silicon compound as a raw material gas and an oxygen gas as a decomposition gas. Formation of the gas barrier layer is carried out so that a carbon content of the gas barrier layer in the thickness direction repeatedly changes more than two times from high value, via intermediate value, low value and intermediate value, to high value.

RELATED APPLICATIONS

This a continuation of U.S. Ser. No. 11/663,140, filed on Mar. 16, 2007,now U.S. Pat. No. 8,652,625, which is a U.S. National Phase under 35U.S.C. §371 of International Application No. PCT/JP2005/016377, filed onSep. 7, 2005.

TECHNICAL FIELD

The present invention relates to a transparent gas barrier film mainlyused in packaging material for food and medicinal products and aspackaging for electronic devices, or used in display material as plasticsubstrates for organic electroluminescence elements and liquid crystalsand the like.

BACKGROUND OF THE INVENTION

Gas barrier films in which a thin layer of a metal oxide such asaluminum oxide, magnesium oxide, or silicon oxide is formed on a plasticsubstrate or on a film surface, have been widely used in packaging ofproducts which require a barrier for various types of gases such aswater vapor and oxygen as well as in packaging to prevent changes in thequality of foods, industrial products, medicinal products and the like.Aside from the use for packaging, gas barrier films are also used assubstrates for liquid crystal displays, solar cells, organicelectroluminescence (EL) and the like.

An aluminum foil is widely used as the packaging material in these kindsof fields, but disposal after use is problematic and in addition, theseare basically opaque materials and the fact that the content cannot bechecked from the outside is also problematic. In addition, transparencyis required for display materials, and these opaque materials cannot beused.

Meanwhile, a polyvinylidene chloride resin or copolymer resin materialsof vinylidene chloride and another polymer or a material which isprovided with gas barrier properties by coating these vinylidenechloride resins on polypropylene resins, polyester resins or polyamideresins are widely used as packaging materials in particular, but at theincineration step, chlorine based gases are generated and this iscurrently problematic in view of environment preservation. Furthermore,the gas barrier properties are not necessarily sufficient and so theycannot be used in fields where high barrier properties are required.

In particular, in transparent substrates which are used more and more inliquid crystal display elements and organic EL elements in particular,in addition to the requirement in recent years to be light weight andlarge in size, there are also high level requirements of long termreliability and a high degree of freedom with regards to configuration.In addition, film substrates such as transparent plastic are now beingused instead of glass substrates which easily break, and are heavy anddifficult in increasing screen size. For example, Japanese PatentPublication Open to Public Inspection (hereafter referred to as JP-A)Nos. 2-251429 and 6-124785 disclose an example in which a polymer filmis used as the substrate for an organic electroluminescence element.

However, there has been a problem in that the gas barrier property of afilm substrate such as a transparent plastic film is inferior to that ofa glass substrate. For example, when such a substrate having aninsufficient gas barrier property is used as a substrate of the organicelectroluminescence element, water vapor and air may penetrate thesubstrate to degrade the organic layer, resulting in loss of lightemitting properties or durability. In addition, when a polymer substrateis used as an electronic device substrate, oxygen may pass through thepolymer substrate, penetrate and diffuse into the electronic devicecausing problems such as deterioration of the device or making itimpossible to maintain the required degree of vacuum in the electronicdevice.

In order to solve this type of problem, a gas barrier film substrate inwhich a thin metal oxide layer is formed on a film substrate is known.Layers in which silicon oxide (Patent Document 1) or aluminum oxide(Patent Document 2) is deposited on the plastic film are also known asthe gas barrier used in packaging material or liquid crystal element. Ineither case, currently the layers have water vapor barrier propertiesthat do not exceed about 2 g/m²/day or oxygen transmission that does notexceed about 2 ml/m²/day. In recent years, due to the EL displays whichrequire greater gas barrier properties, increasing size of liquidcrystal displays and development of high definition displays, watervapor barrier of around 10⁻³ g/m²/day is required for the gas barrierproperties of the film substrate.

A gas barrier film having a structure in which a compact ceramic layerand flexible polymer layer which softens impact from outside arealternately laminated a number of times, is proposed as a method formeeting these requirements of high water vapor barrier properties (seePatent Document 3 for example). However, because the composition of theceramic layer and the polymer layer is generally different, adhesion atthe respective adhesion interfaces deteriorate and cause productdeterioration such as layer stripping. In particular, the occurrence ofadhesion deterioration is outstanding under severe conditions such ashigh temperature and high humidity or exposure to ultraviolet radiationfor an extended period, and thus early improvement is desired.

-   Patent Document 1 Examined Japanese Patent Publication No. 53-12953-   Patent Document 2 Japanese Patent Publication Open to Public    Inspection (hereafter referred to as JP-A) No. 58-217344-   Patent Document 3 U.S. Pat. No. 6,268,695

SUMMARY OF THE INVENTION

The present invention was conceived in view of the above-describedproblems and an object thereof is to provide a transparent gas barrierfilm which has excellent adhesion even when stored under severeconditions, and has favorable transparency and gas barrier resistance.

One of the aspects of the present invention to achieve the above objectis a transparent gas barrier film comprising a substrate having thereona gas barrier layer comprising at least a low density layer and a highdensity layer, wherein one or more intermediate density layers aresandwiched between the low density layer and the high density layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1( a) is a pattern diagram showing an example of the layercomposition of a gas barrier film of the present invention and FIG. 1(b) is the density profile thereof.

FIG. 2( a) is a pattern diagram showing another example of the layercomposition of a gas barrier film of the present invention and FIGS. 2(b) and 2(c) are the density profiles thereof.

FIG. 3 is a schematic view showing an example of the jet typeatmospheric plasma discharge treatment device useful in the presentinvention.

FIG. 4 is a schematic view showing an example of the type of atmosphericplasma discharge treatment device which processes substrate betweenfacing electrodes that is useful in the present invention.

FIG. 5 is a perspective view showing an example of the conductive basemetal for the rotatable roll electrodes and the dielectric structurethat covers the base metal.

FIG. 6 is a perspective view showing an example of the conductive basemetal for the square pillar-shaped electrodes and the dielectricstructure coated thereon.

FIGS. 7 a and 7 b are illustrative graphs showing the results of thedensity profile measured by the X-ray reflectance method and the carboncontent profile measured by the XPS surface analysis method.

FIGS. 8 a and 8 b are illustrative graphs showing other results of thedensity profile measured by the X-ray reflectance method and the carboncontent profile measured by the XPS surface analysis method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The above object of the present invention is achieved by the followingstructures.

(1) A transparent gas barrier film comprising a substrate having thereona gas barrier layer comprising at least a low density layer and a highdensity layer, wherein

one or more intermediate density layers are sandwiched between the lowdensity layer and the high density layer.

(2) The transparent gas barrier film of Item (1), wherein the lowdensity layer, the intermediate density layer and the high density layereach contain a common element.

(3) The transparent gas barrier film of Item (1) or (2), wherein

the transparent gas barrier film comprises a unit comprising the lowdensity layer, the intermediate density layer, the high density layerand the intermediate density layer laminated in that order from thesubstrate side; and

the unit is repeatedly laminated twice or more.

(4) The transparent gas barrier film of any one of Items (1) to (3),wherein

a density distribution in the low density layer, the intermediatedensity layer or the high density layer exhibits a graded structurealong a thickness direction.

(5) The transparent gas barrier film of any one of Items (1) to (4),wherein

the low density layer, the intermediate density layer and the highdensity layer each comprise at least one compound selected from thegroup consisting of silicon oxide, silicon oxynitride, silicon nitrideand aluminum oxide.

(6) The transparent gas barrier film of any one of Items (1) to (5),wherein

the high density layer comprises silicon oxide; and

a density of the high density layer at a maximum density region is 2.1g/cm³ or more.

(7) The transparent gas barrier film of any one of Items (1) to (6),wherein the low density layer comprises silicon oxide; and

a density of the low density layer at a minimum density region is 2.0g/cm³ or less.

(8) The transparent gas barrier film of any one of Items (1) to (5),wherein

the high density layer comprises silicon oxynitride; and

a density of the high density layer at a maximum density region is 2.2g/cm³ or more.

(9) The transparent gas barrier film of any one of Items (1) to (6),wherein

the low density layer comprises silicon oxynitride; and

a density of the low density layer at a minimum density region is 2.0g/cm³ or less.

(10) The transparent gas barrier film of any one of Items (1) to (5),wherein

the high density layer comprises silicon nitride; and

a density of the high density layer at a maximum density region is 2.2g/cm³ or more.

(11) The transparent gas barrier film of any one of Items (1) to (6),wherein

the low density layer comprises silicon nitride; and

a density of the low density layer at a minimum density region is 2.0g/cm³ or less.

(12) The transparent gas barrier film of any one of Items (1) to (5),wherein

the high density layer comprises aluminum oxide; and

a density of the high density layer at a maximum density region is 3.5g/cm³ or more.

(13) The transparent gas barrier film of any one of Items (1) to (6),wherein

the low density layer comprises aluminum oxide; and

a density of the low density layer at a minimum density region is 3.0g/cm³ or less.

The following is a detailed description of the preferred embodiment forrealizing the present invention.

As a result of diligent studies in view of the problems described above,the inventors of the present invention found out that a transparent gasbarrier film with excellent adhesion even when stored under severeconditions, favorable transparency and gas barrier resistance isrealized by a transparent gas barrier film comprising a gas barrierlayer that is formed on a substrate from at least a low density layerand a high density layer, wherein one or more intermediate densitylayers are between the low density layer and the high density layer.

Furthermore, in addition to the structure specified above, it wasdiscovered that the target effects of the present invention wereexpressed even more when: the low density layer, the intermediatedensity layer and the high density layer include the same elements;given that from the substrate side, a low density layer, an intermediatedensity layer a high density layer, and an intermediate density layerform one unit and this unit is laminated twice or more; including agraded structure in which the density distribution in the low densitylayer, the intermediate density layer or the high density layer changescontinuously in the thickness direction; the low density layer, theintermediate density layer and the high density layer includes at leastone substance selected from silicon oxide, silicon nitride oxide,silicon nitride and aluminum oxide; using silicon oxide, siliconoxynitride, silicon nitride or aluminum oxide in the high density layeror the low density layer and using the maximum density or the minimumdensity of that layers as prescribed conditions.

The transparent gas barrier film according to Items (1)-(13) of thepresent invention can obtain the same effects by employing thepreferable aspects described in the following.

(A) A transparent gas barrier film comprising a substrate having thereona gas barrier layer containing at least a high carbon content layer anda low carbon content layer, wherein one or more intermediate carboncontent layers are sandwiched between the low carbon content layer andthe high carbon content layer.

(B) The transparent gas barrier film of Item (A), wherein the low carboncontent layer, the intermediate carbon content layer and the high carboncontent layer include the same elements.

(C) The transparent gas barrier film of Item (A) or (B), wherein giventhat from the substrate side, the high carbon content layer, theintermediate carbon content layer, the low carbon content layer, and theintermediate carbon content layer form one unit, lamination of this unitis repeated twice or more.

(D) The transparent gas barrier film of any one of Items (A)-(C),wherein the carbon content distribution in the low carbon content layer,the intermediate carbon content layer or the high carbon content layerhas a content gradient in the thickness direction.

(E) The transparent gas barrier film of Item (D), wherein the compoundforming the carbon content gradient is silicon oxide and the minimumcarbon content is no more than 1.0%

(F) The transparent gas barrier film of Item (D), wherein the compoundforming the carbon content gradient is silicon oxide and the maximumcarbon content is no less than 20.0%

(G) The transparent gas barrier film of Item (D), wherein the compoundforming the carbon content gradient is silicon nitride and the minimumcarbon content is no more than 1.0%

(H) The transparent gas barrier film of Item (D), wherein the compoundforming the carbon content gradient is silicon nitride and the maximumcarbon content is no less than 20.0%.

(I) The transparent gas barrier film of Item (D), wherein the compoundforming the carbon content gradient is aluminum oxide and the minimumcarbon content is no more than 1.0%

(J) The transparent gas barrier film of Item (D), wherein the compoundforming the carbon content gradient is aluminum oxide and the maximumcarbon content is no less than 20.0%.

The following is a detailed description of the present invention.

The transparent gas barrier film of the present invention contains a gasbarrier layer that is formed on a substrate from at least a low densitylayer and a high density layer, wherein one or more layers of anintermediate density layer are sandwiched between the low density layerand the high density layer.

Given that average density of low density layer with the lowest averagedensity is d₁ and the average density of high density layer with thehighest average density is d₂, the intermediate density layer in thepresent invention is defined as the layer with the average density d₃which satisfies the condition of Equation (1).(d ₁+3d ₂)/4≧d ₃≧(3d ₁ +d ₂)/4  Equation (1)

The density of each of the component layers stipulated in the presentinvention can be determined using the known analytic means, but in thepresent invention values determined by the X-ray reflectance method areused.

An outline of the X-ray reflectance method in X-ray diffractionHandbook, Page 151 (edited by Rigaku Denki Corporation 2000, Publishedby International Academic Printing Co., Ltd) or Chemical Industries,January 1999 No. 22 can be referred to perform the method.

The following is a specific example of the method for measurement usefulin the present invention.

MXP21 manufactured by Mac Science Co., Ltd. is used as the measuringdevice. The device is operated at 42 kV and 500 mA using copper as theX-ray light source. A multilayer parabola mirror is used as the incidentmonochrometor. An incidence slit of 0.05 mm×5 mm and a light receivingslit of 0.03 mm×20 mm is used. Measurements are done using the FT methodhaving 2θ/θ mode from 0 degree to 5 degrees with step size of 0.005degrees and scanning speed of 10 seconds per step. Curve fitting isperformed using the Reflectivity Analysis Program Vector. 1 manufacturedby Mac Science Co., Ltd. for the obtained by the reflectance curve, andthe parameters are determined such that the residual sum of squares ofthe measured value and the fitting curve is a minimum. The thickness anddensity of the laminated layer can be obtained from the parameters. Thelayer thickness evaluation of the laminated layer in the presentinvention can also be determined by the X-ray reflectance measurementsdescribed above.

In the transparent gas barrier film of the present invention given thatfrom the substrate side, a low density layer, an intermediate densitylayer, a high density layer, and an intermediate density layer, arelaminated in that order to form one unit, the unit is preferablylaminated twice or more, or in other words eight layers or more arelaminated, and more preferably, the number of laminated units is 2-4.

In addition, in transparent gas barrier film of the present invention,the density distribution in the low density layer, the intermediatedensity layer or the high density layer preferably has a gradedstructure in the thickness direction.

FIG. 1( a) is a pattern diagram showing an example of the layerconstitution of a gas barrier film of the present invention and FIG. 1(b) is the density profile thereof.

The transparent gas barrier film 1 of the present invention has astructure in which layers of different densities are laminated on thesubstrate 2. In the present invention, the intermediate density layer 4of the present invention is provided between the low density layer 3 andthe high density layer 5, and an intermediate density layer 4 isprovided on the high density layer, and if the structure comprising thelow density layer, intermediate density layer, high density layer, andintermediate density layer form one unit, FIG. 1 shows and example inwhich 2 units are laminated. In this case, the density distributioninside the each density layer is even, and the density changes betweenadjacent layers are step-wise. It is to be noted that in FIG. 1, theintermediate density layer 4 is shown as one layer, but a structurehaving two layers or more may be employed if necessary.

FIG. 2( a) is a pattern diagram showing another example of the layerconstitution of a gas barrier film of the present invention and FIGS. 2(b) and 2(c) are the density profile thereof.

The layer constitution is a two unit constitution which is the same asthat shown in 1 above, but the density distribution in the low densitylayer, intermediate density layer, or high density layer has a gradedstructure in the thickness direction.

In the density distribution profile shown in FIG. 2, the densitydistribution in the low density layer 3-1 which is in contact with thesubstrate 2 has a continuous density change pattern in which the densityof the surface contacting the substrate has the minimum value and has angradation (+gradation) in which density increases in the thicknessdirection, and the intermediate density layer 4-1 which is laminated onthe low density layer 3-1 also has the +gradation. In this case, theintermediate density layer 4-1 employs a structure with two or morelayers.

Next, in FIG. 2( b), the density pattern in the layer of the highdensity layer 5-1 laminated on the intermediate density layer 4-1 is anexample of the convex density distribution which shows the maximum valueof the density inside the layer. Also, in FIG. 2( c), an example isshown which has even density distribution in the layers, as is the casein the high density layer 5 of FIG. 1. Next, the intermediate densitylayer 4-2 on the high density layer 5-1 is formed such that the densitydecreases in the thickness direction (−gradation) to exhibit acontinuous density change pattern. The low density layer 3-2 is furtherlaminated on the intermediate density layer 4-2, but the densitydistribution pattern of the low density layer 3-2 in this case may bethe convex density distribution example which shows the minimum value ofdensity in the layers, or may be the example which has even densitydistribution in the layers as is the case in the low density layer 3shown in FIG. 1.

In the transparent gas barrier film of the present invention, as shownin FIGS. 1 and 2, the method for controlling the density differencebetween the layers to the desired conditions is not particularlylimited, however, in the layer formation using the atmospheric plasmamethod described hereinafter that is favorably applied in the presentinvention, a proper density can be obtained by suitably selecting amethod, namely, the fixed electrodes group is inclined with respect tothe rotatable roll electrode to change the space between the electrodes;or the type and supply amount of supplied layer forming material or theoutput condition of electric power at the time of plasma discharge issuitably selected.

In addition, as shown in FIG. 2, in the case where density changes areperformed continuously in the layers also, it is preferable that theatmospheric plasma method is used, and a proper density can be obtainedby continuously controlling the supply amount of the layer formationmaterial at the time of forming the layer, or the output conditions atthe time of plasma discharge.

In addition, in the case where density between the layers iscontinuously changed as is shown in FIG. 2( b), in the presentinvention, the interface between the layers is defined as the region inwhich the slope of the density distribution pattern changes.

The transparent gas barrier film of the present invention is formed fromlayers of different densities including the low density layer,intermediate density layer, high density layer, but a preferable aspectof the transparent gas barrier film is one including a gas barrier layerformed on a substrate of at least a low carbon content layer and a highcarbon content layer, wherein one or more medium carbon content layersare sandwiched between the low carbon content layer and the high carboncontent layer.

Given that average carbon content of the high carbon content layer withthe highest carbon content is n₁ and average carbon content of the lowcarbon content layer with the lowest carbon content is n₂, the mediumcarbon content layer of the present invention, is defined as the layerwith the average carbon content n₃ which satisfies the conditionsstipulated by Equation (2).(n ₁+3n ₂)/4≦n ₃≦(3n ₁ +n ₂)/4  Equation (2)

The carbon content of each of the component layers stipulated in thepresent invention can be obtained using the known analytic means.

The atomic concentration which indicates the carbon content ratio in thepresent invention is calculate by the XPS method described below, and isdefined by the following.Atomic concentration=Number of carbon atoms/Total number of atoms×100.

In the present invention, the ESCALAB-200R manufactured by VG Scientificis used as the XPS surface analyzer. More specifically, Mg is used inthe X-ray anode and measured at output 600 W (acceleration pressure 15kV, Emission current 40 mA). The energy resolution is set to be 1.5eV-1.7 eV when half breadth of pure Ag 3d5/2 peaks is measured.

The measurement is done by first measuring the bond energy 0 eV-1100 eVrange at data fetching intervals of 1.0 ev and determining whether allthe elements have been detected.

Next, all the elements except the etching ions are narrow-scanned forthe photoelectron peak at the maximum applied intensity with a datafetching interval of 0.2 eV and then the specter is measured for eachelement.

The obtained specter is transferred to Common Data Processing System(preferably after Ver. 2.3) manufactured by VAMAS-SCA-JAPAN in order toprevent difference in the content ratio calculation results fromoccurring due differences in the measuring device or computer and thevalue for the content ratio of each element which is a target foranalysis (carbon, oxygen, silicon, and titanium) is determined as atomicconcentration: at %.

Before the determination process is performed, calibration of the countscale for each element is performed, and then 5 point smoothing processis performed. In the determination process, peak intensity (cps*eV) inwhich the background is removed is used. In the background process, theShirley method is used. The Shirley method can be referred to in D. A.Shirley, Phys, Rev., B5, 4709 (1972).

The carbon content profile between the carbon content layers in thetransparent gas barrier film of the present invention can be the same asthe patterns shown in FIG. 1 and FIG. 2 mentioned above. That is to saythe low density layer in FIGS. 1 and 2 corresponds to the high carboncontent layer and the high density layer corresponds to the low carboncontent layer and thus the density pattern and the carbon contentpattern show reversal profiles.

In the gas barrier film of the present invention, the method forcontrolling the carbon content difference between the layers to thedesired conditions is not particularly limited, but in the layerformation of the atmospheric plasma method described hereinafter that ispreferably applied in the present invention, the layer is obtained bysuitably selecting a method, namely, the fixed electrodes group isinclined with respect to the rotatable roll electrode to change thespace between the electrodes; or the type and supply amount of suppliedlayer forming material or the output condition of electric power at thetime of plasma discharge is suitably selected.

Next, the component elements of the transparent gas barrier film of thepresent invention will be described,

<Gas Barrier Layer>

First, the gas barrier layer formed from the low density layer, theintermediate density layer, and the high density layer of the presentinvention will be described.

The constitution of the gas barrier layer of the present invention isnot particularly limited provided that permeation of oxygen and watervapor is blocked. The material for forming the gas barrier layer ispreferably inorganic oxides, and specific examples of the materialinclude silicon oxide, aluminum oxide, silicon oxynitride, siliconnitride, magnesium oxide, zinc oxide, indium oxide, and tin oxide. Thethickness of the gas barrier layer in the present invention varies andis suitably selected in accordance with the type of material used andoptimal conditions for the constitution, but it is preferably in therange of 5-2000 nm. If the thickness of the gas barrier is less than theabove range, an even layer cannot be obtained and is difficult to obtaingas barrier properties. In addition, thickness of the gas barrier isgreater than the above range, it is difficult to maintain flexibility ofthe gas barrier film and there is the possibility that cracks and thelike may occur in the gas barrier film due to external factors such asbending and pulling after layer formation.

The gas barrier layer of the present invention may be formed bysubjecting the material described below to the spraying method, spincoating method, sputtering method, ion assist method, plasma CVD methoddescribed hereinafter, or the plasma CVD method under atmosphericpressure or approximately atmospheric pressure.

However, in wet methods such as the spray method and the spin coatingmethods, obtaining molecular level (nm level) smoothness is difficult,and because a solvent is used, and the substrate which is describedhereinafter is an organic material, there is the shortcoming thatmaterials or solvents that can be used are limited. Thus, in the presentinvention, a layer that is formed using the plasma CVD method or thelike is preferable, and the atmospheric plasma CVD method in particularis preferable in view that a reduced pressure chamber and the like isunnecessary, high speed layer formation becomes possible, and it is ahigh productivity layer formation method. By forming the transparent gasbarrier layer using the atmospheric plasma CVD method, it becomespossible to form a layer which is even and has surface smoothnessrelatively easily. The plasma CVD method is the plasma CVD method underatmospheric pressure or approximately atmospheric pressure, and it isparticularly preferable that the plasma CVD method under atmosphericpressure or approximately atmospheric pressure is used. The layerformation conditions in the plasma CVD method is described in detailhereinafter.

It is preferable that the gas barrier layer is obtained by using theplasma CVD method or the plasma CVD method performed under atmosphericpressure or near atmospheric pressure because a metal carbide, metalnitride, metal oxide, metal sulfide, metal halide and their mixturethereof (such as metal oxide-nitride, metal oxide-halide, and metalnitride-carbide) can be optionally produced by selecting an organometalcompound as the raw material, decomposition gas, decompositiontemperature and applying electric power.

For example, silicon oxide is formed by using a silicon compound as theraw material and oxygen as the decomposition gas, and zinc sulfide isformed by using a zinc compound as the raw material and carbon disulfideas the decomposition gas. In the space of plasma, very high activelycharged particles or active radicals exist in high density. Therefore,plural steps of chemical reaction are accelerated in very high rate inthe plasma space and the elements being in the plasma space is convertedto the chemically stable compound within extremely short duration.

The state of the inorganic raw material may be gas, liquid or solid atroom temperature as far as the raw material contains a typical metalelement or a transition metal element. The gas can be directlyintroduced into the discharging space and the liquid or solid is usedafter vaporized by a method such as heating bubbling or applyingultrasonic wave. The raw material may be used after diluted by asolvent. An organic solvent such as methanol, ethanol, n-hexane and amixture thereof can be used for such the solvent. The influence of thesolvent can be almost ignored because the solvent is decomposed intomolecular or atomic state by the plasma discharge treatment.

Examples of such the organic compound include a silicon compound such assilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane,tetra-iso-propoxsilane, tetra-n-butoxysilane, tetra-t-butoxysilane,dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane,diphenylsimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane,phenyltriethoxysilane, (3,3,3-trifluoropropyl)trimethoxysilane,hexamethyldisyloxane, bis(dimethylamino)dimethylsilane,bis(dimethylamino)methylvinylsilane, bis(ethylamino)dimethylsilane,N,O-bis(trimethylsilyl)acetoamide, bis(trimethylsilyl)carbodiimide,diethylaminotrimethylsilane, dimethylaminodimethylsilane,hexamethyldisilazane, heaxamethylcyclotrisilazane, heptamethylsilazane,nonamethyltrisilazane, octamethylcyclotetrasilazane,tetrakisdimethyaminosilazane, tetraisocyanate silane,tetramethyldisilazane, tris(dimethylamino)silane, triethoxyfluorosilane,allyldimethylsilane, allyltrimethylsilane, benzyltrimethylsilane,bis(trimethylsilyl)acetylene, 1,4-bistrimethylsilyl-1,3-butadiine,di-t-butylsilane, 1,3-disilabutane, bis(trimethylsilyl)methane,cyclopentanedienyltrimethylsilane, phenyldimethylsilane,phenyltrimethylsilane, propagyltrimethylsilane, tetramethylsilane,trimethylsilylacetylene, 1-(trimethylsilyl)-1-propine,tris(trimethylsilyl)methane, tris(trimethylsilyl)silane,vinyltrimethylsilane, hexamethyldisilane, octamethylcyclotetrasiloxane,tetramethylcyclotetrasiloxane, heaxmethylcycrotetrasiloxane andM-silicate 51.

Examples of the titanium compound include titanium methoxide, titaniumethoxide, titanium isopropoxide, titanium tetraisoboroxide, titaniumn-butoxide, titanium isopropoxide(bis-2,4-pentanedionate), titaniumdiisopropoxide(bis-2,4-ethylacetoacetate), titaniumdi-n-butoxide(bis-2,4-pentanedionate), titanium caetylacetonate andbutyl titanate dimer.

Examples of the zirconium compound include zirconium n-propoxide,zirconium n-butoxide, zirconium t-butoxide, zirconium tri-n-butoxideacetylacetonate, zirconium di-n-butoxide bisacetylacetonate, zirconiumacetylacetonate, zirconium acetate and zirconiumheaxafluoropentanedionate.

Examples of the aluminum compound include aluminum ethoxide, aluminumtriisopropoxise, aluminum isopropoxide, aluminum n-butoxide, aluminums-butoxide, aluminum t-butoxide, aluminum acetylacetonate andtriethyldialuminum tri-s-butoxide.

Examples of the boron compound include diborane, boron fluoride, boronchloride, boron bromide, borane-diethyl ether complex, borane-THFcomplex, borane-dimethyl sulfide complex, borane trifluoride-diethylether complex, triethylborane, trimethoxyborane, triethoxyborane,tri(isopropoxy)borane, borazole, trimethylborazole, triethylborazole andtriisopropylborazole.

Examples of the tin compound include teraethyltin, tetramethyltin,diaceto-di-n-butyltin, terabutyltin, tetraoctyltin, tetraethoxytin,methyltriethoxytin, diethyldiethoxytin, triisopropylethoxytin,diethyltin, dimethyltin, diisopropyltin, dibutyltin, diethoxytin,dimethoxtin, diisopropoxytin, dibutoxytin, tin dibutylate, tinacetoacetonate, ethyltin acetoacetonate, ethoxytin acetoacetonate,dimethyltin acetoacetonate, tin hydride and tin halide such as tindichloride and tin tetrachloride.

Examples of another organic metal compound include antimony ethoxide,arsenic triethoxide, barium 2,2,6,6-tetramethylheptanedionate, berylliumacetylacetonate, bismuth hexafluoropnetanedionate, dimethylcadmium,calcium 2,2,6,6-tetramethylheptanedionate, chromiumtrifluoropentanedionate, cobalt cetylacetonate, copperhexafluoropentanedionate, magnesium heaxfluoropentane-dionate-dimethylether complex, gallium ethoxide, tetraethoxygermanium, hafniumt-butoxide, hafnium ethoxide, indium acetylacetonate, indium2,6-dimethylaminoheptanedionate, ferrocene, lanthanum isopropoxide, leadacetate, tetraethyllead, neodium acetylacetonate, platinumhexafluoropentanedionate, trimethylcyclopentanedienylplatinum, rhodiumdicarbonylacetylacetonate, strontium 2,2,6,6-tetramethylheptanedionate,tantalum methoxide, tantalum trifluoroethoxide, tellurium ethoxide,tungsten ethoxide, vanadium triisopropoxideoxide, magnesiumhexafluorocetylacetonate, zinc acetylacetonate and diethylzinc.

Examples of the decomposition gas for decomposing the raw material gascontaining the metal to form an inorganic compound include hydrogen gas,methane gas, acetylene gas, carbon monoxide gas, carbon dioxide gas,nitrogen gas, ammonium gas, nitrogen suboxide gas, nitrogen oxide gas,nitrogen dioxide gas, oxygen gas, steam, fluorine gas, hydrogenfluoride, trifluoroalcohol, trifluorotoluene, hydrogen sulfide, sulfurdioxide, carbon disulfide and chlorine gas.

Various kinds of metal carbide, metal nitride, metal oxide, metal halideand metal sulfide can be obtained by suitably selecting the metalelement-containing raw material gas and the decomposition gas.

Such the reactive gas is mixed with a discharging gas capable of easilybecoming into a plasma state and sent into the plasma dischargegeneration apparatus. Nitrogen gas and/or an atom of Group 18 ofperiodic table such as helium, neon, argon, krypton, xenon and radon areused for such the discharging gas. Of these, nitrogen, helium and argonare preferably used.

The discharging gas and the reactive gas are mixed to prepare a mixedgas and supplied into the plasma discharge (plasma generating) apparatusto form the layer. The reactive gas is supplied in a ratio of thedischarging gas to whole mixture of the gases of 50% or more althoughthe ratio is varied depending on the properties of the layer to beformed.

In the gas barrier layer of the present invention, the organic compoundincluded in the gas barrier is preferably SiOx, SiNy, or SiOxNy (x=1-2,y=0.1-1), and SiOx is preferable in view of the transmission of watercontent, the transmission of light rays, and the suitability ofatmospheric plasma CVD.

The inorganic compound of the present invention may be combined with theabove organic silicon compound as well as oxygen gas or nitrogen gas ina prescribed proportion, and a layer including at least one of O atomsand the N atoms and Si atoms can be obtained. It is to be noted that anN atom is preferably included in view of the fact that SiO₂ has hightransmission and the gas barrier properties are slightly reduced andsome water passes through. That is to say, given that the ratio of thenumber of oxygen atoms to that of nitrogen atoms is x:y, x/(x+y) ispreferably 0.95 or less, and more preferably 0.80 or less. Thus, in thegas barrier layer of the present invention, the light ray transmission Tis preferably 80% or more.

It is to be noted that if the proportion of N atoms is large,transparency decreases, and in SiN where x=0, there is some amount ofyellowing. Thus the specific proportion of the oxygen atoms and thenitrogen atoms should be determined in accordance with application. Forexample, for applications which require transparency such as when thelayer is formed on a light emitting surface side with respect to thelight emitting element in the display device, x/(x+y) is 0.4 or more and0.95 is preferable as there is balance between transparency and waterrepellency. In addition, for application in which it is preferable thatlight is absorbed or blocked as for antireflection layers provided onthe back surface of the light emitting element of the display device,x/(x+y) is preferably not less than 0 and less than 0.4.

Thus, the gas barrier layer of the present invention is preferablytransparent. When the gas barrier layer is transparent, it becomespossible for the gas barrier film to be transparent, and it can be usedin applications such as the transparent substrate for organic ELelements.

<Substrate>

The substrate used in the transparent gas barrier film of the presentinvention is not particularly limited provided it is a layer that isformed of an organic material that can hold the gas barrier layer thathas the barrier properties.

Specific examples of the films which may be used are as follows.Homopolymers such as ethylene, polypropylene, butene, or copolymers orpolyolefin (PO) resins such as copolymers; amorphous polyolefin resins(APO) such as cyclic polyolefins; polyester resins such as polyethyleneterephthalate (PET) and polyethylene 2,6-naphthalate (PEN); polyamide(PA) resins such as nylon 6, nylon 12 and copolymer nylon; polyvinylalcohol resins such as polyvinyl alcohol (PVA) resins and ethylenevinylalcohol copolymers (EVOH); polyimide (PI) resins; polyether imide (PEI)resins; polysulfone (PS) resins; polyether sulfone (PES) resins;polyether ether ketone (PEEK) resins; polycarbonate (PC) resins;polyvinyl butyrate (PVB) resins; polyarylate (PAR) resins; fluorineresins such as ethylene-tetrafluoroethylene copolymers (ETFE), ethylenetrifluorochloride (PFA), ethylene tetrafluoride-perfluoroalkyl vinylether copolymers (FEP), vinylidene fluoride (PVDF), vinyl fluoride(PVF), and perfluoroethylene-perfluoropropylene-perfluorovinyl ethercopolymers (EPA). Also, besides the above resins, photocurable resinssuch as resin compositions comprising an acrylate compound having aradical reactive unsaturated compound, resin compositions including theacrylate compound and a mercapto compound having a thiol group and resincompositions obtained by dissolving oligomers such as epoxyacrylate,urethaneacrylate, polyesteracrylate, or polyether acrylate in apolyfunctional acrylate monomer or mixtures of these resins may be used.Furthermore, laminates obtained by laminating one or two or more ofthese resins by means of laminating or coating may be used as thesubstrate film.

These materials may be used singly or may be suitably mixed. Of these,commercially available products such as Zeonex or Zeonor (manufacturedby Nippon Zeon), ARTON which is an amorphous cyclopolyolefein resin film(manufactured by JSR), Pureace which is polycarbonate film (manufacturedby Teijin), Konica tack KC4UX and KC8UX which are cellulose triacetatefilms (manufactured by Konica Minolta) may be suitably used.

The substrate is preferably transparent. When the substrate and thelayer formed on the substrate is also transparent, it becomes possiblefor the gas barrier film to be transparent, and thus it can be used fortransparent substrates such as organic EL elements.

The substrate of the present invention using the resin listed above maybe either an unstretched film or a stretched film.

The substrate according to the present invention may be produced using aconventionally known usual method. For example, a resin as the rawmaterial is melted using an extruder, extruded using a cyclic die orT-die and cooled quickly, and thus an unstretched substrate which issubstantially amorphous and non-oriented can be produced. Also, anunstretched substrate is stretched in the direction of the flow(vertical axis) of the substrate or in the direction perpendicular(horizontal axis) to the direction of the flow of the substrate by usinga known method such as uniaxial orientation, tenter-type sequentialbiaxial stretching, tenter-type simultaneous biaxial stretching, ortubular-type simultaneous biaxial stretching, and thus a stretchedsubstrate can be produced. The magnification of stretching in this caseis preferably 2 to 10 in both of the vertical axis direction and thehorizontal axis direction, buy it may be suitably selected to correspondwith a resin as the raw material of the substrate.

Also, the substrate according to the present invention may be processedby surface treatment such as corona treatment, flame treatment, plasmatreatment, glow discharge treatment, surface roughing treatment, orchemical treatment.

Furthermore, an anchor coating-agent layer may be formed on the surfaceof the substrate according to the present invention with the purpose ofimproving adhesion to the vacuum deposition layer. Examples of anchorcoating agent to be used in the anchor coating-agent layer include apolyester resin, isocyanate resin, urethane resin, acryl resin,ethylenevinyl alcohol resin, denatured vinyl resin, epoxy resin,denatured styrene resin, denatured silicon resin, and alkyl titanate,and these may be used either singly or in combinations of two or more.Conventionally known additives may be added to the anchor coatingagents. The substrate may be coated with the above anchor coating agentby using a known method such as roll coating, gravure coating, knifecoating, dip coating, or spray coating and the solvents or diluents areremoved by drying, and thus anchor coating can be carried out. Theamount of the above anchor coating agent to be applied is preferablyabout 0.1 to 5 g/m² (dry condition).

A long product which is wound to be roll-like is convenient as thesubstrate cannot be generally specified because it differs depending onuses of the obtained gas barrier film, and the thickness of thesubstrate is not particularly limited when the gas barrier film is usedfor packaging. However, based on suitability for packaging material, itis preferably in the range of 3 to 400 μm, and more preferably 6 to 30μm.

In the addition, the substrate used in the present invention ispreferably a layer having a thickness of 10 to 200 μm and morepreferably 50 to 100 μm.

Also, the water vapor transmission rate for the gas barrier film of thepresent invention is preferably 1.0 g/m²/day or less when measured bythe JIS K7129 B method, when used for applications which require a highdegree of water vapor barrier properties such as organic EL displays andhigh resolution color liquid crystal displays. Furthermore, in the casewhere the gas barrier film is used for organic EL displays, even ifalmost negligible, dark spot which grow are generated, and the life ofthe display is sometimes is shortened to a great extent and thus thewater vapor transmission rate of the gas barrier film is preferably 0.1g/m²/day.

<<Plasma CVD Method>>

Next, the plasma CVD method and the plasma CVD method under atmosphericpressure, which can be preferably employed to form the low densitylayer, the intermediate density layer and the high density layer of thepresent invention in the production method of the transparent gasbarrier film of the present invention will be explained further indetail.

The plasma CVD method of the present invention will now be explained.

The plasma CVD method is also called as plasma enhanced chemical vapordeposition method or PECVD method, by which a layer of various inorganicsubstances having high covering and contact ability can be formed on anysolid-shaped body without excessively raising the temperature of thesubstrate.

The usual CVD method (chemical vapor deposition method) is a method inwhich the evaporated or sublimated organic metal compound is stuck ontothe surface of the substrate at high temperature and thermallydecomposed to form a thin layer of a thermally stable inorganicsubstance. Such the usual CVD method (also referred to as a thermal CVDmethod) cannot be applied for layer forming on the plastic substratesince the substrate temperature is not less than 500° C.

In the plasma CVD method, a space in which gas is in the plasma state (aplasma space) is generated by applying voltage in the space near thesubstrate. Evaporated or sublimated organometal compound is introducedinto the plasma space and decomposed, followed by being blown onto thesubstrate to form a thin layer of inorganic substance. In the plasmaspace, the gas of a high ratio of several percent is ionized into ionsand electrons, and the electron temperature is very high while the gasis held at low temperature. Accordingly, the organometal compound whichis the raw material of the inorganic layer can be decomposed bycontacting with the high temperature electrons and the low temperaturebut excited state of ion radicals. Therefore, the temperature of thesubstrate on which the inorganic layer is formed can be kept low, andthus the layer can be sufficiently formed even on a plastic substrate.

However, since it is necessary to apply an electric field to the gas forionizing the gas into the plasma state, the film has usually beenproduced in a space reduced in the pressure of from about 0.101 kPa to10.1 kPa. Accordingly the plasma CVD equipment has been large and theoperation has been complex, resulting in suffering from a problem ofproductivity.

In the plasma CVD method under near atmospheric pressure, not only thereduced pressure is not necessary, resulting in a high productivity, butalso a high layer forming rate is obtained since the density of theplasma is higher. Further a notably flat film compared to that obtainedvia usual plasma CVD method is obtained, since mean free path of the gasis considerably short under the high pressure condition namely anatmospheric pressure. Thus obtained flat film is preferable with respectto the optical property or the gas barrier property. As described above,in the present invention, the plasma CVD method under near atmosphericpressure is more preferable than the plasma CVD method under vacuum.

The apparatus for forming the polymer layer or the gas barrier layer bythe plasma CVD method under the atmospheric pressure or near atmosphericpressure is described in detail below.

An example of the plasma layer forming apparatus to be used in the gasbarrier material producing method of the present invention for formingthe low density layer, the intermediate density layer and the highdensity layer is described referring FIGS. 3 to 6. In the drawings, F isa long length film as an example of the substrate.

FIG. 3 is a schematic drawing of an example of an atmospheric pressureplasma discharge apparatus by jet system available for the presentinvention.

The jet system atmospheric pressure discharge apparatus is an apparatushaving a gas supplying means and an electrode temperature controllingmeans, which are not described in FIG. 3 (shown in FIG. 4 later),additionally to a plasma discharge apparatus and an electric fieldapplying means with two electric power sources.

A plasma discharge apparatus 10 has facing electrodes constituted by afirst electrode 11 and a second electrode 12. Between the facingelectrodes, first high frequency electric field with frequency of ω₁,electric field strength of V₁ and electric current of I₁ supplied by thefirst power source 21 is applied by the first electrode 11 and secondhigh frequency electric field with frequency of ω₂, electric fieldstrength of V₂ and electric current of I₂ supplied by the second powersource 32 is applied by the second electrode 12. The first power source21 can supply high frequency electric field strength higher than that bythe second power source 22 (V₁>V₂) and the first power source 21 cansupply frequency ω₁ lower than the frequency ω₂ supplied by the secondpower source 22.

A first filter 23 is provided between the first electrode 11 and thefirst power source 12 so that the electric current from the first powersource 21 is easily passed to the first electrode 11 and the currentfrom the second power source 22 is difficulty passed to the firstelectrode 11 by grounding the current from the second power source 22 tothe first power source 21.

A second filter 24 is provided between the first electrode 12 and thefirst power source 22 so that the electric current from the second powersource 22 is easily passed to the second electrode and the current fromthe first power source 21 is difficulty passed to the second electrodeby grounding the current from the first power source 21 to the secondpower source.

Gas G is introduced from a gas supplying means such as that shown inFIG. 4 into the space 13 (discharging space) between the facing firstelectrode 11 and the second electrode 12, and discharge G° is generatedby applying high frequency electric field from the first and secondelectrodes so as to make the gas to plasma state and the gas in theplasma state is jetted G′ to the under side (under side of the paper inthe drawing) of the facing electrodes so as to fill the treatment spaceconstituted by under surfaces of the facing electrodes and the substrateF by the gas in the plasma state, and then the thin layer is formed nearthe treatment position 14 on the substrate F conveyed from the bulk roll(unwinder) of the substrate by unwinding or from the previous process.During the layer formation, the electrodes are heated or cooled by amedium supplied from the electrode temperature controlling means shownin FIG. 4 which will be mentioned later trough the pipe. It ispreferable to suitably control the temperature of the electrodes becausethe physical properties and the composition are varied sometimesaccording to the temperature of the substrate on the occasion of theplasma discharge treatment. As the medium for temperature control, aninsulation material such as distilled water and oil is preferably used.It is desired that the temperature at the interior of the electrode isuniformly controlled so that ununiformity of temperature in the widthdirection and length direction of the substrate is made as small aspossible on the occasion of the plasma discharge treatment.

A plurality of the atmospheric pressure plasma discharge treatingapparatus by the jetting system can be directly arranged in series fordischarging the same gas in plasma state at the same time. Therefore,the treatment can be carried out plural times at high rate. Furthermore,a multilayer composed of different layers can be formed at once byjetting different gases in plasma state at the different apparatuses,respectively.

FIG. 4 is a schematic drawing of an example of the atmospheric pressuredischarge apparatus for treating the substrate between the facingelectrodes effectively applied for the present invention.

The atmospheric pressure plasma discharge apparatus of the presentinvention at least has a plasma discharge apparatus 30, an electricfield applying means having two electric power sources 40, a gassupplying means 50 and an electrode temperature controlling means 60.

In the apparatus shown in FIG. 4, a thin layer is formed by the plasmadischarge treatment carried out on the substrate F in a charge space 32constituted between a rotatable roller electrode (first electrode) 35and a group of square pillar-shaped electrodes (second electrode) 36. InFIG. 4, an electric field is formed by a pair of square pillar-shapedelectrodes (second electrode) 36 and a rotatable roller electrode (firstelectrode) 35, and using this unit, for example, a low density layer isformed. FIG. 4 illustrates an example including five such units, and, byindependently controlling, for example, the supplying raw material andoutput voltage in each unit, the laminating type transparent gas barrierlayer as prescribed in the present invention can be continuously formed.

In each discharging space 32 (between the facing electrodes) formedbetween the rotatable roller electrode (first electrode) 35 and thesquare pillar-shaped fixed electrode group (second electrode) 36, thefirst high frequency electric field with frequency ω₁, electric fieldstrength V₁ and electric current I₁ supplied from a first power source41 is applied to the rotatable roller electrode (first electrode) 35,and a second high frequency electric field with frequency ω₂, electricfield strength V₂ and electric current I₂ supplied from thecorresponding second power source 42 is applied to each squarepillar-shaped fixed electrode group (second electrode) 36, respectively.

A first filter 43 is provided between the rotatable roller electrode(first electrode) 35 and the first power source 41 and the first filter43 is designed so that the electric current from the first power source41 to the first electrode is easily passed and the electric current fromthe second power source 42 to the first electrode is difficulty passedby grounding. Furthermore, a second filter 44 is provided between thesquare pillar-shaped fixed electrode (second electrode) 36 and thesecond power source 42 and the second filter 44 is designed so that theelectric current from the second power source 42 to the second electrodeis easily passed and the electric current from the first power source 41to the second electrode is difficultly passed by grounding.

In the present invention, it is allowed to use the rotatable rollerelectrode 35 as the second electrode and the square pillar-shaped fixedelectrode 35 as the first electrode. In all cases, the first powersource is connected to the first electrode and the second power sourceis connected to the second electrode. The first electrode preferablysupplies high frequency electric field strength larger than that of thesecond power source (V₁>V₂). The frequency can be ω₁<ω₂.

The electric current is preferably I₁<I₂. The electric current I₁ of thefirst high frequency electric field is preferably from 0.3 mA/cm² to 20mA/cm² and more preferably from 1.0 mA/cm² to 20 mA/cm². The electriccurrent I₂ of the second high frequency electric field is preferablyfrom 10 mA/cm² to 100 mA/cm² and more preferably from 20 mA/cm² to 100mA/cm².

Gas G generated by a gas generating apparatus 51 of the gas generatingmeans 50 is controlled in the flowing amount and introduced into aplasma discharge treatment vessel 31 through a gas supplying opening.

The substrate F is unwound from a bulk roll not shown in the drawing orconveyed from a previous process and introduced into the apparatustrough a guide roller 64. Air accompanied with the substrate is blockedby a nipping roller 65. The substrate F is conveyed into the spacebetween the square pillar-shaped fixed electrode group and the rotatableroller electrode (first electrode) 35 while contacting and putting roundwith the rotatable roller electrode. Then the electric field is appliedby both of the rotatable roller electrode (first electrode) and thesquare pillar-shaped fixed electrode group (second electrode) 36 forgenerating discharging plasma in the space 32 (discharging space)between the facing electrodes. A thin layer is formed by the gas in theplasma state on the substrate while contacting and putting round withthe rotatable roller electrode 35. After that, the substrate F is woundup by a winder not shown in the drawing or transported to a next processthrough a nipping roller 66 and a guide roller 67.

The exhaust gas G′ after the treatment is discharged from an exhaustopening 53.

For cooling or heating the rotatable roller electrode (first electrode)35 and the square pillar-shaped fixed electrode group (second electrode)36 during the thin layer formation, a medium controlled in thetemperature by an electrode temperature controlling means 60 is sent tothe both electrodes by a liquid sending pump P through piping 61 tocontrol the temperature of the electrodes from the interior thereof. 68and 69 are partition plates for separating the plasma dischargingtreatment vessel 31 from the outside.

FIG. 5 shows an oblique view of the structure of an example of therotatable roller electrode shown in FIG. 4 composed of anelectroconductive metal base material and a dielectric material coveringthe base material.

In FIG. 5, the roller electrode 35 a is composed of an electroconductivemetal base 35A covered with a dielectric material 35B. The electrode isconstituted so that the temperature controlling medium such as water andsilicone oil can be circulated in the electrode for controlling thesurface temperature of the electrode during the plasma dischargingtreatment.

FIG. 6 shows an oblique view of the structure of an example of therotatable roller electrode composed of an electroconductive metal basematerial and a dielectric material covering the core material.

In FIG. 6, a square pillar-shaped electrode 36 a is composed of anelectroconductive metal base 36A having a cover of dielectric material36B as same as shown in FIG. 5 and the electrode constitutes a metalpipe forming a jacket so that the temperature can be controlled duringthe discharging.

The plural square pillar-shaped fixed electrodes are arranged along thecircumstance larger than that of the roller electrode and thedischarging area of the electrode is expressed by the sum of the area ofthe surface of the square pillar-shaped electrodes facing to therotatable roller electrode 35.

The square pillar-shaped electrode 36 a may be a cylindrical electrodebut the square pillar-shaped electrode is preferably used in the presentinvention since the square pillar-shaped electrode is effective forincreasing the discharging extent (discharging area) compared with thecylindrical electrode.

The roller electrode 35 a and the square pillar-shaped electrode 36 ashown in FIGS. 5 and 6 are each prepared by thermal spraying ceramics asthe dielectric material 35B or 36B on the metal base 35A or 35B andsubjecting to a sealing treatment using a an inorganic sealing material.The thickness of the ceramics dielectric material may be about 1 mm. Asthe ceramics material for the thermal spraying, alumina and siliconnitride are preferably used, among them alumina, which can be easilyprocessed, is particularly preferred. The dielectric layer may be alining treated dielectrics formed by lining an inorganic material.

For the electroconductive metal base material 35A and 36B, a metal suchas metal titanium and a titanium alloy, silver, platinum, stainlesssteel, aluminum and iron, a composite material of iron and ceramics anda composite material of aluminum and ceramics are usable and themetallic titanium and titanium alloy are particularly preferable by thelater-mentioned reason.

The distance between the facing first and second electrodes is theshortest distance between the surface of the dielectric layer and thesurface of the electroconductive metal base material of the otherelectrode when the dielectric layer is provided on one of theelectrodes, and is the shortest distance between the dielectric layersurfaces when the dielectric material is provided on both of theelectrodes. Though the distance between the electrodes is decidedconsidering the thickness of the dielectric material provided on theelectroconductive metal base material, the strength of the appliedelectric field and the utilizing object of the plasma, the thickness ispreferably from 0.1 to 20 mm and particularly preferably from 0.5 to 2mm in any cases from the viewpoint for performing uniform discharge.

Details of the electroconductive metal base material and the dielectricuseful in the present invention material will be described later.

Though the plasma discharging treatment vessel 31 is preferably a glassvessel such as Pyrex® glass, a metal vessel can be used when the vesselcan be insulated from the electrodes. For example, one constituted by aframe of aluminum or stainless steel covered on inside thereof bypolyimide resin or one constituted by such the thermal sprayed withceramics for giving insulating ability are usable. The both sidesurfaces in parallel of the both electrodes (near the core materialsurface) is preferably covered with the above-described material.

Examples of the first power source (high frequency power source)employed in the atmospheric pressure plasma processing apparatus of thepresent invention include the following power sources:

Reference Number Maker Frequency Product name A1 Shinko Denki  3 kHzSPG3-4500 A2 Shinko Denki  5 kHz SPG5-4500 A3 Kasuga Denki 15 kHzAGI-023 A4 Shinko Denki 50 kHz SPG50-4500 A5 Heiden Kenkyusho 100 kHz*PHF-6k A6 Pearl Kogyo 200 kHz  CF-2000-200k A7 Pearl Kogyo 400 kHz CF-2000-400k

Any of the above commercially available power sources can be used in thepresent invention.

Examples of the second power source (high frequency power source includethe following power sources:

Reference Number Maker Frequency Trade name B1 Pearl Kogyo 800 kHzCF-2000-800k B2 Pearl Kogyo 2 MHz CF-2000-2M B3 Pearl Kogyo 13.56 MHzCF-2000-13M B4 Pearl Kogyo 27 MHz CF-2000-27M B5 Pearl Kogyo 150 MHzCF-2000-150M

Any of the above commercially available power sources can be used in thepresent invention.

In the power sources above, “*” represents an impulse high frequencypower supply (100 kHz in continuous mode) manufactured by HeidenKenkyusho, and others are high frequency power supplies capable ofapplying electric field with only continuous sine wave.

In the present invention, it is preferable that the power source whichenables to keep a uniform and stable discharge state with supplying suchan electric field is employed in the atmospheric pressure plasmadischarge apparatus.

In the present invention, when power is supplied across the facingelectrodes, power (power density) of not less than 1 W/cm² is suppliedto the second electrode (the second high frequency electric field) so asto excite the discharge gas to generate plasma. The energy is then givento the reactive gas, whereby a thin film is formed and give theresulting energy to the discharge gas. The upper limit of the powersupplied to the second electrode is preferably 50 W/cm², and morepreferably 20 W/cm². The lower limit of the power supplied is preferably1.2 W/cm². The discharge surface area (cm²) refers to the surface areaof the electrode at which discharge occurs.

Further, the power density can be enhanced while the uniformity of thesecond high frequency electric field is maintained, by supplying power(power density) of not less than 1 W/cm² to the first electrode (thefirst high frequency electric field), whereby more uniform plasma withhigher density can be produced, resulting in improving both film formingrate and film quality. The power supplied to the first electrode ispreferably not less than 5 W/cm². The upper limit of the power suppliedto the first electrode is preferably 50 W/cm².

Herein, the waveform of the high frequency electric field is notspecifically limited. There are a continuous oscillation mode which iscalled a continuous mode with a continuous sine wave and a discontinuousoscillation mode which is called a pulse mode carrying out ON/OFFdiscontinuously, and either may be used, however, a method supplying acontinuous sine wave at least to the second electrode side (the secondhigh frequency electric field) is preferred to obtain a uniform filmwith high quality.

The quality of the film can also be controlled by controlling theelectric power of the second electrode.

It is necessary that electrodes used in the atmospheric pressure plasmafilm forming method is structurally and functionally resistant to theuse under severe conditions. Such electrodes are preferably those inwhich a dielectric is coated on a metal base material.

In the dielectric coated electrode used in the present invention, thedielectric and metal base material used in the present invention arepreferably those in which their properties meet. For example, oneembodiment of the dielectric coated electrodes is a combination ofconductive metal base material and a dielectric in which the differencein linear thermal expansion coefficient between the conductive basematerial and the dielectric is not more than 10×10⁻⁶/° C. The differencein linear thermal expansion coefficient between the conductive metalbase material and the dielectric is preferably not more than 8×10⁻⁶/°C., more preferably not more than 5×10⁻⁶/° C., and most preferably notmore than 2×10⁻⁶/° C. Herein, the linear thermal expansion coefficientis a known physical value specific to materials.

Combinations of conductive base material and dielectric having adifference in linear thermal expansion coefficient between them fallingwithin the range as described above will be listed below.

1. A combination of pure titanium or titanium alloy as conductive metalbase material and a thermal spray ceramic layer as a dielectric layer

2: A combination of pure titanium or titanium alloy as conductive metalbase material and a glass lining layer as a dielectric layer

3: A combination of stainless steel as conductive metal base materialand a thermal spray ceramic layer as a dielectric layer

4: A combination of stainless steel as conductive metal base materialand a glass lining layer as a dielectric layer

5: A combination of a composite of ceramic and iron as conductive metalbase material and a thermal spray ceramic layer as a dielectric layer

6: A combination of a composite of ceramic and iron as conductive metalbase material and a glass lining layer as a dielectric layer

7: A combination of a composite of ceramic and aluminum as conductivemetal base material and a thermal spray ceramic layer as a dielectriclayer

8: A combination of a composite of ceramic and aluminum as conductivemetal base material and a glass lining layer as a dielectric layer.

In the viewpoint of the difference in the linear thermal expansioncoefficient, preferable are above 1, 2, and 5-8, but specificallypreferable is 1.

In the present invention, as a metal base metal material, titanium isuseful with respect to the above-mentioned property. By using titaniumor a titanium alloy as the metal base material and by using the abovedielectric, the electrode can be used under a severe condition for along time without deterioration of the electrode, specifically, a crack,peeling or elimination.

As an atmospheric pressure plasma discharge apparatus employable in thepresent invention, for example, those disclosed in JP-A Nos. 2004-68143and 2003-49272 and WO02/48428 are included, together with describedabove.

EXAMPLES

The following is a detailed description of the present invention usingexamples, however, the present invention is not limited thereto.

Example 1 Production of the Transparent Gas Barrier Film 1

A transparent gas barrier film in which three units each comprising alow density layer, an intermediate density layer, a high density layer,and an intermediate density layer with the profile constitution (layerdensity distribution pattern) shown in FIG. 1 are formed on apolyethylene naphthalate film with a thickness of 100 μm (manufacturedby Teijin Dupont and called PEN hereinafter) using the atmosphericplasma discharge treatment device and discharge conditions below.

(Atmospheric Plasma Discharge Treatment Device)

A set of a roll electrode coated by a dielectric substance and aplurality of square pillar-shaped electrodes are produced as shown belowusing the atmospheric plasma discharge treatment device of FIG. 4.

In the roll electrode, or the first electrode, a jacket roll base metalmaterial made of titanium alloy T64 having a cooling device usingcooling water is coated with an alumina spray layer with high densityand high adhesion according to an atmospheric plasma method such thatthe roll diameter is 1000 mm. Meanwhile, in the second electrode, or asquare pillar-shaped electrode, the square hollow cylinder made oftitanium T64 is coated in thickness of 1 mm under the same condition asfor the above dielectric to produce a square pillar-shaped fixedelectrode group facing each other.

Twenty-four of these square cylinder are disposed around the rotatableroll electrode with an facing electrode interval of 1 mm. The totaldischarge area of the group of square pillar-shaped fixed electrodes is14,400 cm² which is obtained by 150 cm (width direction length)×4 cm(conveying direction length)×24 electrodes. It is noted that each has asuitable filter.

During plasma discharge, the temperature adjustment and insulation isdone such that the first electrode (rotatable roll electrode) and secondelectrode (square pillar-shaped fixed electrode group) are 80° C., androtatable roll electrode is rotated by a drive and layer formation isperformed. Of the twenty-four square pillar-shaped fixed electrodes,four from the upstream side are used for forming the first layerdescribed below (low density layer 1), the next six are used for formingthe second layer described below (intermediate density layer 1) and thenext eight are used for forming the third layer (high density layer 1),and the remaining six are used to form the fourth layer (intermediatedensity layer 2), and the conditions are set so that the four layers arelaminated in one pass. These conditions are repeated twice to form thetransparent gas barrier film 1.

(First Layer: Low Density Layer 1)

Plasma discharge was carried out under the conditions below to form alow density layer 1 having a thickness of approximately 90 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.8 volume %  Raw material gas:Hexamethyldisiloxane 0.2 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas 5.0 volume %<Power Condition: Only the Power Source at the First Electrode Side isUsed>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Applied Electronics Corporation    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

The density of the first layer (low density layer) formed above wasmeasured by the X-ray reflectance method using aforementioned MXP21manufactured by Mac Science Co., Ltd. and a result of 1.90 was obtained.

(Second Layer: Intermediate Density Layer 1)

Plasma discharge was carried out under the conditions below to form anintermediate density layer 1 having a thickness of approximately 90 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.9 volume %  Raw material gas:Hexamethyldisiloxane 0.1 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas 5.0 volume %<Power Conditions: Only the Power Source for the First Electrode Side isUsed>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

The density of the second layer (intermediate density layer) formedabove was measured by the X-ray reflectance method using aforementionedMXP21 manufactured by Mac Science Co., Ltd. and a result of 2.05 wasobtained.

(Third Layer: High Density Layer 1)

Plasma discharge was carried out under the conditions below to form ahigh density layer 1 having a thickness of approximately 90 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.9 volume %  Raw material gas:Hexamethyldisiloxane 0.1 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas 5.0 volume %<Power Conditions>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Applied Electronics Corporation    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

Second Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Pearl Kogyo Co., Ltd.    -   Frequency: 13.56 MHz    -   Output density: 10 W/cm²

The density of the third layer (high density layer) formed above wasmeasured by the X-ray reflectance method using aforementioned MXP21manufactured by Mac Science Co., Ltd. and a result of 2.20 was obtained.

(Fourth Layer: Intermediate Density Layer 2)

The intermediate density layer 2 is formed under the same conditions asthe second layer (intermediate density layer 1).

(Fifth Layer to Twelfth Layer)

The same conditions for the formation of the first layer to the fourthlayer (one unit) are repeated twice to form the transparent gas barrierfilm 1.

<Evaluation of the Transparent Gas Barrier Film>

[Measurement of Density Distribution]

The results of the density profile measured by the X-ray reflectancemethod using the MXP21 manufactured by Mac Science Co., Ltd. are shownin FIG. 7 a.

[Measurement of Carbon Content]

The results of the carbon content profile that is measured using theESCALAB-200R manufactured by VG Scientific Corporation as the XPSsurface analyzer are shown in FIG. 7 b.

[Evaluation of Stability]

(Adhesion Evaluation)

Evaluation of adhesion for the transparent gas barrier film 1 formedabove was performed using a JIS K 5400 compliant cross-cut adhesiontest, and favorable results were obtained.

(Evaluation of Shelf Life)

Evaluation of adhesion for the transparent gas barrier film 1 formedabove was performed using a JIS K 5400 compliant cross-cut adhesion testafter immersion in 98° C. hot water for 48 hours and there was nodeterioration in adhesion properties and favorable results wereobtained.

(Evaluation of Ultraviolet Light Resistance)

Evaluation of adhesion for the transparent gas barrier film 1 formedabove was performed using a JIS K 5400 compliant cross-cut adhesion testafter irradiation with 1500 mW/cm² ultraviolet rays for 96 hours using ametal halide lamp and there was no deterioration in adhesion propertiesand extremely favorable results were obtained.

[Evaluation of Gas Barrier Properties]

[Measurement of Water Vapor Transmission Rate]

The water vapor transmission rate for the unprocessed transparent gasbarrier film 1 and samples of the produced in “Shelf life” and“Ultraviolet light resistance” were measured using a JIS K 7129Bstipulated method, and the water vapor transmission rate for all of thesamples was 0.01 g/m²/day or less.

(Measurement of Oxygen Transmission Rate)

The oxygen transmission rate for the unprocessed transparent gas barrierfilm 1 and samples of the produced in “Shelf life” and “Ultravioletlight resistance” were measured using a method stipulated by JIS K7126B, and the oxygen transmission rate for all of the samples was 0.01ml/m²/day or less.

Example 2 Production of the Gas Barrier Film 2

A transparent gas barrier film 2 in which 3 units of a low densitylayer, an intermediate density layer, a high density layer, and anintermediate density layer with the profile constitution (pattern inwhich the layer density has an graded distribution) shown in FIG. 2 areformed on the substrate described in Example 1 using the sameatmospheric plasma discharge treatment device as that used in Example 1.It is to be noted that in formation of the density gradation pattern,the second electrode (square pillar-shaped fixed electrode group) isinclined from the standard interval of 1 mm with respect to the firstelectrode (rotatable roll electrode) and the interval between the pairof second electrodes (square pillar-shaped fixed electrode group) ischanged.

Of the twenty-four square pillar-shaped fixed electrodes, four from theupstream side are used for forming the first layer described below (lowdensity layer 1), the next two are used for forming the second layerdescribed below (intermediate density layer 1), the next two are usedthe next two are used for forming the fourth layer (intermediate densitylayer 3), the next two are used for forming the fifth layer (highdensity layer 1), the next two are used for forming the sixth layer(high density layer 2), the next two are used for forming the seventhlayer (intermediate density layer 4), the next two are used for formingthe eighth layer (intermediate density layer 5), the next two are usedfor forming the ninth layer (intermediate density layer 6), and theremaining four are used to form the tenth layer (low density layer 2),and the conditions are set so that the first layer to the tenth layerare laminated in one pass. The conditions are repeated twice to form thetransparent gas barrier film 2.

(First Layer: Low Density Layer 1)

Plasma discharge was carried out under the conditions below to form alow density layer 1 having a thickness of approximately 90 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.8 volume %  Raw material gas:Hexamethyldisiloxane 0.2 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas 5.0 volume %<Power Condition: Only the Power Source at the First Electrode Side isUsed>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Applied Electronics Corporation    -   Frequency: 80 kHz    -   Output density: 10 W/cm²    -   Electrode incline angle: −2°

The density of the first layer (low density layer 1) formed above wasmeasured by the X-ray reflectance method using aforementioned MXP21manufactured by Mac Science Co., Ltd. and the density changed from 1.90to 1.99 at the graded structure.

(Second Layer: Intermediate Density Layer 1)

Plasma discharge was carried out under the conditions below to form anintermediate density layer 1 having a thickness of approximately 30 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.85 volume %  Raw material gas:Hexamethyldisiloxane 0.15 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas  5.0 volume %<Power Conditions: Only the Power Source for the First Electrode Side isUsed>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²    -   Electrode incline angle: −2°

The density of the second layer (intermediate density layer 1) formedabove was measured by the X-ray reflectance method using aforementionedMXP21 manufactured by Mac Science Co., Ltd. and the density changed from1.99 to 2.05 at the graded structure.

(Third Layer: Intermediate Density Layer 2)

Plasma discharge was carried out under the conditions below to form anintermediate density layer 2 having a thickness of approximately 30 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.85 volume %  Raw material gas:Hexamethyldisiloxane 0.15 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas  5.0 volume %<Power Conditions>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

Second Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Pearl Kogyo Co., Ltd    -   Frequency: 13.56 MHz    -   Output density: 5 W/cm²    -   Electrode incline angle: −2°

The density of the third layer (intermediate density layer 2) formedabove was measured by the X-ray reflectance method using aforementionedMXP21 manufactured by Mac Science Co., Ltd. and the density changed from2.05 to 2.10 at the graded structure.

(Fourth Layer: Intermediate Density Layer 3)

Plasma discharge was carried out under the conditions below to form anintermediate density layer 3 having a thickness of approximately 30 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.9 volume %  Raw material gas:Hexamethyldisiloxane 0.1 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas 5.0 volume %<Power Conditions>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

Second Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Pearl Kogyo Co., Ltd    -   Frequency: 13.56 MHz    -   Output density: 5 W/cm²    -   Electrode incline angle: −2°

The density of the fourth layer (intermediate density layer 3) formedabove was measured by the X-ray reflectance method using aforementionedMXP21 manufactured by Mac Science Co., Ltd. and the density changed from2.10 to 2.16 at the graded structure.

(Fifth Layer: High Density Layer 1)

Plasma discharge was carried out under the conditions below to form ahigh density layer 1 having a thickness of approximately 45 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.85 volume % Raw material gas:Hexamethyldisiloxane  0.15 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas  5.0 volume %<Power Conditions>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

Second Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Pearl Kogyo Co., Ltd    -   Frequency: 13.56 MHz    -   Output density: 10 W/cm²    -   Electrode incline angle: −2°

The density of the fifth layer (high density layer 1) formed above wasmeasured by the X-ray reflectance method using aforementioned MXP21manufactured by Mac Science Co., Ltd. and the density changed from 2.16to 2.20 at the graded structure.

(Sixth Layer: High Density Layer 2)

Plasma discharge was carried out under the conditions below to form ahigh density layer 2 having a thickness of approximately 45 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.85 volume % Raw material gas:Hexamethyldisiloxane  0.15 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas  5.0 volume %<Power Conditions>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm.sup.2        Second Electrode Side    -   Type of power source: High frequency power source manufactured        by Pearl Kogyo Co., Ltd    -   Frequency: 13.56 MHz    -   Output density: 10 W/cm²    -   Electrode incline angle: +2°

The density of the sixth layer (high density layer 2) formed above wasmeasured by the X-ray reflectance method using aforementioned MXP21manufactured by Mac Science Co., Ltd. and the density changed from 2.20to 2.16 at the graded structure.

(Seventh Layer: Intermediate Density Layer 4)

Plasma discharge was carried out under the conditions below to form anintermediate density layer 4 having a thickness of approximately 30 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.9 volume %  Raw material gas:Hexamethyldisiloxane 0.1 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas 5.0 volume %<Power Conditions>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

Second Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Pearl Kogyo Co., Ltd    -   Frequency: 13.56 MHz    -   Output density: 5 W/cm²    -   Electrode incline angle: +2°

The density of the seventh layer (intermediate density layer 4) formedabove was measured by the X-ray reflectance method using aforementionedMXP21 manufactured by Mac Science Co., Ltd. and the density changed from2.16 to 2.10 at the graded structure.

(Eight Layer: Intermediate Density Layer 5)

Plasma discharge was carried out under the conditions below to form anintermediate density layer 5 having a thickness of approximately 30 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.85 volume % Raw material gas:Hexamethyldisiloxane  0.15 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas  5.0 volume %<Power Conditions>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

Second Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Pearl Kogyo Co., Ltd    -   Frequency: 13.56 MHz    -   Output density: 5 W/cm²    -   Electrode incline angle: +2°

The density of the eighth layer (intermediate density layer 5) formedabove was measured by the X-ray reflectance method using aforementionedMXP21 manufactured by Mac Science Co., Ltd. and the density changed from2.10 to 2.05 at the graded structure.

(Ninth Layer: Intermediate Density Layer 6)

Plasma discharge was carried out under the conditions below to form anintermediate density layer 6 having a thickness of approximately 30 nm.

Discharge gas: Nitrogen gas 94.85 volume % Raw material gas:Hexamethyldisiloxane  0.15 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas  5.0 volume %<Power Conditions: Only Power Source at First Electrode Side is Used>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²    -   Electrode incline angle: +2°

The density of the ninth layer (intermediate density layer 6) formedabove was measured by the X-ray reflectance method using aforementionedMXP21 manufactured by Mac Science Co., Ltd. and the density changed from2.05 to 1.99 at the graded structure.

(Tenth Layer: Low Density Layer 2)

Plasma discharge was carried out under the conditions below to form alow density layer 1 having a thickness of approximately 90 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.0 volume %  Raw material gas:Hexamethyldisiloxane 1.0 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas 5.0 volume %<Power Conditions: Only Power Source at First Electrode Side is Used>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²    -   Electrode incline angle: +2°

The density of the tenth layer (low density layer 2) formed above wasmeasured by the X-ray reflectance method using aforementioned MXP21manufactured by Mac Science Co., Ltd. and the density changed from 1.99to 1.90 at the graded structure.

(Formation of the Eleventh to Thirtieth Layer)

The formation of the first layer to the tenth layer (one unit) isrepeated twice under the same conditions to form the transparent gasbarrier film 2 which has an graded density structure.

<Evaluation of the Transparent Gas Barrier Film>

[Measurement of Density Distribution]

The results of the density profile measured by the X-ray reflectancemethod using the MXP21 manufactured by Mac Science Co., Ltd. are shownin FIG. 8 a.

[Measurement of Carbon Content]

The results of the carbon content profile that is measured using theESCALAB-200R manufactured by VG Scientific Corporation as the XPSsurface analyzer are shown in FIG. 8 b.

[Evaluation of Stability]

(Adhesion Evaluation)

Evaluation of adhesion for the transparent gas barrier film 2 formedabove was performed using a JIS K 5400 compliant cross-cut adhesiontest, and extremely favorable results were obtained.

(Evaluation of Shelf Life)

Evaluation of adhesion transparent gas barrier film 2 formed above wasperformed using a JIS K 5400 compliant cross-cut adhesion test afterimmersion 98° C. hot water for 48 hours and there was no deteriorationin adhesion properties and extremely favorable results were obtained.

(Evaluation of Ultraviolet Light Resistance)

Evaluation of adhesion transparent gas barrier film 2 formed above wasperformed using a JIS K 5400 compliant cross-cut adhesion test afterirradiation with 1500 mW/cm² ultraviolet rays for 96 hours using a metalhalide lamp and there was no deterioration in adhesion properties andfavorable results were obtained.

[Evaluation of Gas Barrier Properties]

[Measurement of Water Vapor Transmission Rate]

The water vapor transmission rate for the unprocessed transparent gasbarrier film 2 and samples of the produced in “Shelf life” and“Ultraviolet light resistance” were measured using a JIS K 7129Bcompliant method, and the water vapor transmission rate for all of thesamples was 0.01 g/m²/day or less which represent extremely favorableresults.

(Measurement of Oxygen Transmission Rate)

The oxygen transmission rate for the unprocessed transparent gas barrierfilm 2 and samples of the produced in “Shelf life” and “Ultravioletlight resistance” were measured using JIS K 7126B compliant method, andthe vapor transmission rate for all of the samples was 0.01 ml/m²/day orless which represent extremely favorable results.

Comparative Example 1 Preparation of the Transparent Gas Barrier Film 3

The transparent gas barrier film 3 is prepared in which six 45 nm gasbarrier layers having a uniform density constitution is laminated in onepass on the substrate described in Example 1 using the same atmosphericplasma discharge treatment device as that used in Example 1 such thatlayer formation conditions at all the electrode portions are equal.

(Gas Barrier Layer)

Plasma discharge was carried out under the conditions below to form agas barrier layer having a thickness of 270 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.9 volume %  Raw material gas:Hexamethyldisiloxane 0.1 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas 5.0 volume %<Power Conditions>First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

Second Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Pearl Kogyo Co., Ltd    -   Frequency: 13.56 MHz    -   Output density: 10 W/cm²

The density of gas barrier layer formed above was measured by the X-rayreflectance method using aforementioned MXP21 manufactured by MacScience Co., Ltd. and found to have an even composition density of 2.18

<Evaluation of the Transparent Gas Barrier Film>

[Evaluation of Stability]

(Adhesion Evaluation)

Evaluation of adhesion transparent gas barrier film 3 formed above wasperformed using a JIS K 5400 compliant cross-cut adhesion test, andcracks appeared over the entire surface and adhesion was absolutelyunfavorable.

(Evaluation of Shelf Life)

Evaluation of adhesion transparent gas barrier film 3 formed above wasperformed using a JIS K 5400 compliant cross-cut adhesion test afterimmersion in 98° C. hot water for 48 hours and adhesion deterioratedfurther and product quality was extremely poor.

(Evaluation of Ultraviolet Light Resistance)

Evaluation of adhesion transparent gas barrier film 3 formed above wasperformed using a JIS K 5400 compliant cross-cut adhesion test afterirradiation with 1500 mW/cm² ultraviolet rays for 96 hours using a metalhalide lamp and adhesion deteriorated further and product quality wasextremely poor.

[Evaluation of Gas Barrier Properties]

(Measurement of Water Vapor Transmission Rate)

The water vapor transmission rate for the unprocessed transparent gasbarrier film 2 and samples of the produced in “Shelf life” and“Ultraviolet light resistance” were measured using a JIS K 7129Bcompliant method, and the water vapor transmission rate for thesubstrate by itself without the gas barrier layer was 6.0 g/m²/day orless, while each of the samples was approximately 5.0 g/m²/dayindicating poor water vapor barrier properties.

(Measurement of Oxygen Transmission Rate)

The oxygen transmission rate for the unprocessed transparent gas barrierfilm 2 and samples of the produced in “Shelf life” and “Ultravioletlight resistance” were measured using a JIS K 7126B compliant method,and the oxygen transmission rate for the substrate by itself without thegas barrier layer was 20 ml/m²/day or less, while that of each of thesamples was approximately 15 ml/m²/day indicating poor oxygen barrierproperties.

Comparative Example 2 Preparation of the Transparent Gas Barrier Film 4

The transparent gas barrier film 4 is prepared in which four 1 μm gasbarrier layers having a uniform density composition are laminated on thesubstrate described in Example 1 using the same atmospheric plasmadischarge treatment device as that used in Example 1.

(First Layer: Gas Barrier Layer 1)

Plasma discharge was carried out under the conditions below to form agas barrier layer 1 having a thickness of approximately 1 μm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.8 volume %  Raw material gas:Hexamethyldisiloxane 0.2 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas 5.0 volume %<Power Conditions>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

The density of the first layer (gas barrier layer 1) formed above wasmeasured by the X-ray reflectance method using aforementioned MXP21manufactured by Mac Science Co., Ltd. and was found to have an evencomposition of 1.90.

(Formation of Second Layer to Fourth Layer)

The second to fourth layers were laminated under the same conditions asthe first layer (gas barrier layer 1) to prepare a transparent gasbarrier film 4 with a thickness of approximately 4 μm. The density ofthis transparent gas barrier film 4 was 1.9 over all the layers.

<Evaluation of the Transparent Gas Barrier Film>

[Evaluation of Stability]

(Adhesion Evaluation)

Evaluation of the adhesion transparent gas barrier film 4 formed abovewas performed using a JIS K 5400 compliant cross-cut adhesion test, andresults were obtained that are in the permissible range for practicaluse.

(Evaluation of Shelf Life)

Evaluation of adhesion transparent gas barrier film 4 formed above wasperformed using a JIS K 5400 compliant cross-cut adhesion test afterimmersion in 98° C. hot water for 48 hours and there was nodeterioration in adhesion and results were obtained that are in thepermissible range for practical use.

(Evaluation of Ultraviolet Light Resistance)

Evaluation of adhesion transparent gas barrier film 4 formed above wasperformed using a JIS K 5400 compliant cross-cut adhesion test afterirradiation with 1500 mW/cm² ultraviolet rays for 96 hours using a metalhalide lamp and there was no deterioration in adhesion and results wereobtained that are in the permissible range for practical use.

[Evaluation of Gas Barrier Properties]

(Measurement of Water Vapor Transmission Rate)

The water vapor transmission rate for the unprocessed transparent gasbarrier film 4 and samples of the produced in “Shelf life” and“Ultraviolet light resistance” were measured using a JIS K 7129Bcompliant method, and no gas barrier properties were shown and the watervapor transmission rate for each of the samples was approximately 6.0g/m²/day indicating extremely poor water vapor barrier properties.

(Measurement of Oxygen Transmission Rate)

The oxygen transmission rate for the unprocessed transparent gas barrierfilm 4 and samples produced in “Shelf life” and “Ultraviolet lightresistance” were measured using a JIS K 7126B compliant method, and nogas barrier properties were shown and the oxygen transmission rate foreach of the samples was approximately 20 ml/m²/day indicating pooroxygen transmission properties.

Comparative Example 3 Preparation of the Transparent Gas Barrier Film 5

The transparent gas barrier film 5 is prepared in which two layers eachof a polymer layer (stress relief layer) having the compositiondescribed below and gas barrier layers are laminated on the substratedescribed in Example 1 using the same atmospheric plasma dischargetreatment device as that used in Example 1.

(First Layer: Polymer Layer 1)

Plasma discharge was carried out under the conditions below to form apolymer layer 1 having a thickness of 100 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 99.5 volume % Raw material gas: Polymer 1 0.5 volume % (Nitrogen gas is mixed and vaporized by a vaporizermanufactured by Lintec Commerce Inc.) * Polymer 1: tripropyleneglycoldiacrylate (Aronics M-220 manufactured by Toagosei Co., Ltd.)<Power Conditions>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 20 W/cm²        (Second Layer: Gas Barrier Layer 1)

Plasma discharge was carried out under the conditions below to form gasbarrier layer 1 having a thickness of 100 nm.

<Gas Conditions>

Discharge gas: Nitrogen gas 94.9 volume %  Raw material gas:Hexamethyldisiloxane 0.1 volume % (abbreviated to HMDSO hereinafter)(Nitrogen gas is mixed and vaporized by a vaporizer manufactured byLintec Commerce Inc.) Decomposition gas: Oxygen gas 5.0 volume %<Power Conditions>

First Electrode Side

-   -   Type of power source: High frequency power source manufactured        by OYO Electronic Co., Ltd.    -   Frequency: 80 kHz    -   Output density: 10 W/cm²

Second Electrode Side

-   -   Type of power source: High frequency power source manufactured        by Pearl Kogyo Co., Ltd    -   Frequency: 13.56 MHz    -   Output density: 10 W/cm²

The density of the second layer (gas barrier layer 1) formed above wasmeasured by the X-ray reflectance method using aforementioned MXP21manufactured by Mac Science Co., Ltd. and an even composition of 2.18was obtained.

(Formation of the Third Layer and the Fourth Layer)

A third layer (polymer layer 2) and a fourth layer (gas barrier layer 2)were further laminated using the same conditions as the first layer(polymer layer 1) and the second layer (gas barrier layer 1) to preparethe transparent gas barrier film 5 having a thickness of 400 nm.

<Evaluation of the Transparent Gas Barrier Film>

[Evaluation of Stability]

(Adhesion Evaluation)

Evaluation of the adhesion transparent gas barrier film 5 formed abovewas performed using a JIS K 5400 compliant cross-cut adhesion test, andfavorable results were obtained.

(Evaluation of Shelf Life)

Evaluation of adhesion transparent gas barrier film 5 formed above wasperformed using a JIS K 5400 compliant cross-cut adhesion test afterimmersion in 98° C. hot water for 48 hours and deterioration in adhesionwas confirmed.

(Evaluation of Ultraviolet Light Resistance)

Evaluation of adhesion transparent gas barrier film 5 formed above wasperformed using a JIS K 5400 compliant cross-cut adhesion test afterirradiation with 1500 mW/cm² ultraviolet rays for 96 hours using a metalhalide lamp and deterioration in adhesion was confirmed.

[Evaluation of Gas Barrier Properties]

(Measurement of Water Vapor Transmission Rate)

The water vapor transmission rate for the unprocessed transparent gasbarrier film 5 measured using a JIS K 7129B compliant method was 0.01g/m²/day or less indicating favorable results, but for the samplesproduced in “Shelf life” and “Ultraviolet light resistance”, water vaporbarrier properties deteriorated and was 2.0-3.5 g/m²/day for eachsample.

(Measurement of Oxygen Transmission Rate)

The oxygen transmission rate for the unprocessed transparent gas barrierfilm 5 measured using a JIS K 7126B compliant method was 0.01 ml/m²/dayor less indicating favorable results, but for the samples produced in“Shelf life” and “Ultraviolet light resistance”, oxygen barrierproperties deteriorated and was 8.0-15 ml/m²/day for each sample.

INDUSTRIAL APPLICABILITY

According to the present invention, a transparent gas barrier film canbe provided which has excellent adhesion even when stored under severeconditions, and has favorable transparency and gas barrier resistance.

What is claimed is:
 1. A method for manufacturing a transparent gas barrier film for an organic electroluminescence element comprising a substrate having thereon a gas barrier layer, wherein: the method comprises a step of forming the gas barrier layer on the substrate by a plasma CVD method using an organic silicon compound as a raw material gas and an oxygen gas as a decomposition gas, the gas barrier layer forming step is carried out under a condition so that a carbon content of the gas barrier layer in the thickness direction repeatedly changes more than two times from high value, via intermediate value, low value and intermediate value, to high value, the carbon content is defined by the formula: number of carbon atoms/total number of atoms×100, and a density of the gas barrier layer changes in the range of 1.90 g/cm³ or more and 2.20 g/cm³ or less in the thickness direction.
 2. The method for manufacturing the transparent gas barrier film of claim 1, wherein the carbon content of the gas barrier layer in the thickness direction changes continuously.
 3. The method for manufacturing the transparent gas barrier film of claim 1, wherein an oxygen transmission rate of the transparent gas barrier film is 0.01 g/m²/day or less.
 4. A method for manufacturing a transparent gas barrier film for an organic electroluminescence element comprising a substrate having thereon a gas barrier layer, wherein: the method comprises a step of forming the gas barrier layer on the substrate by a plasma CVD method using an organic silicon compound as a raw material gas and an oxygen gas as a decomposition gas, the gas barrier layer forming step is carried out under a condition so that a carbon content of the gas barrier layer in the thickness direction repeatedly changes more than two times from high value, via intermediate value, low value and intermediate value, to high value, the carbon content is defined by the formula: number of carbon atoms/total number of atoms×100, and a minimum carbon content of the gas barrier layer is 1.0% or less.
 5. The method for manufacturing the transparent gas barrier film of claim 4, wherein the carbon content of the gas barrier layer in the thickness direction changes continuously.
 6. The method for manufacturing the transparent gas barrier film of claim 4, wherein an oxygen transmission rate of the transparent gas barrier film is 0.01 g/m²/day or less.
 7. A method for manufacturing a transparent gas barrier film for an organic electroluminescence element comprising a substrate having thereon a gas barrier layer, wherein: the method comprises a step of forming the gas barrier layer on the substrate by a plasma CVD method using an organic silicon compound as a raw material gas and an oxygen gas as a decomposition gas, the gas barrier layer forming step is carried out under a condition so that a carbon content of the gas barrier layer in the thickness direction repeatedly changes more than two times from high value, via intermediate value, low value and intermediate value, to high value, the carbon content is defined by the formula: number of carbon atoms/total number of atoms×100, and a water vapor transmission rate of the transparent gas barrier film is 0.01 g/m²/day or less.
 8. The method for manufacturing the transparent gas barrier film of claim 7, wherein the carbon content of the gas barrier layer in the thickness direction changes continuously.
 9. The method for manufacturing the transparent gas barrier film of claim 7, wherein an oxygen transmission rate of the transparent gas barrier film is 0.01 g/m²/day or less. 